465

 To replace the whole line where a match
 was found, do this:
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 pattern to find in line - 'six'
 substitution pattern - 'fault'

 check all lines:
 sed 's/.*six.*/fault/' file
 matched lines -> then remove:
 sed '/six/s/.*/fault/' file
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 https://tinyurl.com/ye8j3s8z